Graphite ore beneficiation equipment and beneficiation method

Abstract

The invention relates to graphite graded grinding-cyclone flotation integrated equipment and a beneficiation method, a three-section integrated structure of a graded grinding bin, an intelligent pulp mixing bin and a cyclone flotation bin is adopted, and a traditional intermittent or segmented ore grinding-flotation process is converted into a continuous online closed-loop separation process. A dynamic'dissociation-screening-backflow 'closed loop of raw ore is realized in the grading grinding bin, and coarse particles which are not fully dissociated are returned to a grinding area to be continuously ground in real time through a built-in grading screen and online particle size / scale integrity monitoring; and meanwhile, qualified mineral powder meeting the flotation requirement particle size (the scale integrity is larger than or equal to 92%) is directly conveyed to the intelligent pulp mixing bin through the spiral conveying cylinder for pulp mixing. A coupling mechanism between grinding and flotation is optimized, traditional independent ore grinding time control is omitted, grinding output directly meets the flotation requirement, and therefore efficient recovery of fine-fraction graphite is achieved while the large-flake graphite structure is protected. The fixed carbon content is greater than or equal to 99.5%, and the recovery rate is greater than or equal to 95%.

Description

Technical Field

[0001] This invention relates to the field of graphite ore beneficiation technology, and in particular to a continuous integrated equipment and method that tightly couples grinding and flotation. The aim is to achieve direct matching between grinding output and flotation requirements through equipment structure innovation, eliminating the traditional independent grinding time control link. Background Technology

[0002] In graphite ore beneficiation, grinding is a crucial step, aiming to fully liberate graphite from gangue minerals and preserve the integrity of graphite flakes as much as possible. Traditional processes often employ closed-circuit grinding systems consisting of a grinding mill and a classifier, controlling product particle size by regulating the residence time of the material within the mill (i.e., grinding time). However, this approach has significant drawbacks: the setting of grinding time is empirical and lag-dependent, making it difficult to respond in real-time to changes in feed properties. This easily leads to the destruction of large graphite flakes (+150μm) due to over-grinding, while some fine particles that have met flotation requirements continue to be ground because they are not separated in time, resulting in energy waste and decreased recovery rates.

[0003] Therefore, accurately and quickly separating qualified particles that meet the flotation requirements from the grinding process and directly feeding them into the flotation stage is the core challenge in achieving efficient, low-consumption, and protective large-flake graphite beneficiation. Current technology lacks a continuous, integrated device capable of real-time detection of grinding particle size, immediate re-grinding of unqualified particles, and immediate discharge of qualified particles. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing an integrated graphite classification grinding-cyclone flotation equipment and beneficiation method. Its core idea is to abolish the traditional "time-controlled grinding" mode and replace it with a "demand-driven grinding" online closed-circuit separation mode. Through integrated equipment design and a built-in dynamic screening reflux mechanism, the sole objective of the grinding operation is to produce qualified particles that can be directly and effectively flotated, thereby achieving precise, continuous, and efficient integration of grinding and flotation.

[0005] The equipment is a vertical integrated structure, mainly composed of a cyclone flotation chamber (1), an intelligent slurry conditioning chamber (2), and a classifying and grinding chamber (3) connected by flanges or threads from top to bottom, and supported as a whole on a base (8). Its core innovation lies in the design of the classifying and grinding chamber (3): The chamber is equipped with a dynamic grading screen, which can screen particles in real time during the grinding process.

[0006] The silo is equipped with a spiral conveyor to lift qualified mineral powder from the screen to the upper intelligent slurry mixing silo (2).

[0007] The silo is equipped with a material return channel or structure, which allows coarse particles that fail to pass through the screen (i.e., unqualified particles) to automatically return to the grinding area (such as between the rollers and the grinding disc) to continue grinding.

[0008] The grinding intensity (such as the roller gap) can be adjusted online by the automatic adjustment device (7), but the control logic of grinding is no longer a fixed time, but rather the judgment criterion and stop signal is whether the particles screened in real time meet the flotation requirements (scale integrity ≥ 92%).

[0009] After receiving qualified mineral powder, the intelligent slurry preparation tank (2) prepares a uniformly dispersed slurry through online monitoring and an automatic dosing system. The cyclone flotation tank (1) utilizes the cyclone field to enhance the flotation kinetics process and efficiently separate graphite concentrate.

[0010] Mineral processing methods The mineral processing method based on the above equipment includes the following sequential steps: Dynamic grading and grinding: Raw ore is continuously fed into the grading and grinding chamber (3) and subjected to grinding. Grinding and screening are carried out simultaneously, and the undersize material is detected / judged in real time. If the particle scale integrity is ≥92% (i.e., the physical state of effective flotation collection), it is identified as "qualified mineral powder" and is immediately transported to the intelligent slurry conditioning tank by the screw conveyor (2).

[0011] If the above requirements are not met, the material is returned to the grinding zone via a reflux device to continue dissociation.

[0012] This process does not pre-set or rely on the total grinding time; grinding continues until all the feed ore is converted into "qualified mineral powder".

[0013] Intelligent slurry preparation: qualified mineral powder is mixed with water and composite additives in intelligent slurry preparation tank (2). The slurry dispersion is monitored online (control target ≤5μm), and the addition of reagents is optimized in real time to form a stable and homogeneous flotation slurry.

[0014] Cyclone-enhanced flotation: The prepared slurry enters the cyclone flotation chamber (1). Under the controllable cyclone field and optimized gas-liquid synergistic conditions (such as a gas-liquid ratio of 3:1), graphite particles collide and adsorb efficiently with bubbles, are enriched in the foam layer, and are scraped out and collected by a mechanical scraper (4) to obtain the final concentrate. Beneficial effects

[0015] Eliminate independent grinding time control: Through the integrated closed-loop design of "grinding-screening-reflux-output", the grinding operation directly aims to produce qualified flotation particles, solving the problems of over-grinding, under-grinding or uneven energy consumption caused by the traditional time control mode.

[0016] Great protection for large flake graphite: qualified particles are separated and removed immediately, avoiding unnecessary retention and secondary damage of dissociated large flakes in the mill, and significantly improving the yield and integrity of +150μm large flake graphite (≥92%).

[0017] The process is continuous and efficient, resulting in improved recovery rates: Fine-grained qualified graphite enters the flotation process immediately upon production, avoiding recycling losses in the grinding system and increasing the overall recovery rate (≥95%). Simultaneously, the integrated equipment shortens the process, reducing plant floor space and equipment investment.

[0018] Stable product quality: Precise particle size control and efficient flotation environment ensure a high fixed carbon content (≥99.5%) in the final graphite concentrate. Attached Figure Description

[0019] Figure 1 : Overall assembly isometric drawing of the equipment.

[0020] Figure 2 : A side view of the grading and grinding chamber, showing the internal screen, spiral conveyor, and return path.

[0021] Figure 3 A isometric view of the grading and grinding chamber, showing its connection to the motor drive unit.

[0022] Figure 4 : A side view of the intelligent slurry mixing chamber, showing the installation location of the online monitoring device.

[0023] Figure 5 Isometric view of the intelligent slurry mixing chamber.

[0024] Figure 6 Schematic diagram of the front structure of the intelligent slurry mixing chamber.

[0025] Figure 7 : A schematic diagram of the side structure of the cyclone flotation chamber, showing the biomimetic flow guiding structure and mechanical scraper layout.

[0026] In the diagram: 1. Cyclone flotation chamber; 2. Intelligent slurry conditioning chamber; 3. Classification and grinding chamber; 4. Mechanical scraper; 5. Concentrate trough; 6. Feed inlet; 7. Automatic adjustment device; 8. Base; 9. Motor; 10. Coupling; 11. Monitoring device Detailed Implementation

[0027] The specific working principle of the present invention will be described below with reference to the accompanying drawings: Implementation of the grading and grinding chamber: Ore is continuously fed through the feed inlet (6). The automatic adjustment device (7) can preset the initial gap of the rollers according to the initial particle size distribution of the feed. During the grinding process, the particles are crushed and disintegrated by the rollers, and the fine particles fall through the dynamic grading screen. The online analysis probe (such as an image analyzer or laser particle size analyzer) set below the screen or the preset logic of the screen aperture and conveying conditions determines whether the particles are qualified. Qualified ore powder falls into the bottom receiving area of ​​the central spiral conveyor (3) and is immediately lifted. Unqualified particles (screen material or judged return material) return to the grinding area along the return channel (such as the guide cone surface or the internal circulation path). The whole process is continuous. The mill always works with new feed and return coarse particles until the batch or continuous feed is completely converted into qualified ore powder and output. There is no independent "grinding time" parameter.

[0028] Intelligent slurry preparation tank implementation method: The screw conveyor discharges qualified mineral powder from the top and enters the intelligent slurry preparation tank (2). The tank is equipped with an agitator and connected to water pipes and reagent pipes. The online slurry dispersion monitoring instrument feeds back data to the control system in real time, dynamically adjusting the addition rate of water and composite additives (such as collectors and frothers) to ensure that the slurry is in the optimal flotation state.

[0029] Implementation of cyclone flotation chamber: The slurry after conditioning flows by gravity into the cyclone flotation chamber (1). Air is introduced from the bottom or side, forming a stable cyclone under the action of agitator or fixed guide vanes. The collision probability (P_c) and adhesion stability (P_s) of bubbles and hydrophobic graphite particles in the cyclone field are enhanced. The air intake and slurry flow rate are controlled by adjusting the valve to maintain the optimal gas-liquid ratio (e.g., 3:1). Graphite-adhered foam rises to the liquid surface and is scraped into the concentrate tank (5) by a rotating mechanical scraper (4). Tailings are discharged from the bottom.

[0030]

[0031] in: P: The overall flotation probability of a single particle.

[0032] P_c: Collision probability. The probability of a particle colliding with a bubble. This mainly depends on the particle size, bubble size, and the hydrodynamic conditions (turbulence intensity) of the flotation cell.

[0033] P_a: Adhesion probability. The probability that a particle can successfully detach from the hydration film and stably adhere to the bubble after a collision. This mainly depends on the surface hydrophobicity (floatability) of graphite.

[0034] P_s: Stability probability (or the complement of the detachment probability). The probability that an attached particle cluster can remain stable in the turbulent flow of the flotation cell without detaching from the bubbles. This depends primarily on the adhesion between the particles and the bubbles and the external fluid shear force.

[0035] For graphite ore, due to its naturally good hydrophobicity (excellent floatability), P_a is usually high and relatively stable. Therefore, the influence of particle size (d) on P_c and P_s becomes a key factor determining the flotation probability P.

[0036] According to the flotation probability equation, whether a particle can become a foam product depends on the product of the collision probability, adhesion probability, and detachment probability between the particle and the bubble. The finer the particle, the lower the collision probability and adhesion probability, and the higher the detachment probability, which directly leads to a very low flotation probability and thus a lower recovery rate.

Claims

1. A graphite beneficiation equipment, characterized in that, It includes a base (8), a drive unit mounted on the base, a classifying and grinding chamber (3), an intelligent slurry conditioning chamber (2), and a cyclone flotation chamber (1); The drive device includes multiple sets of motors (12) arranged around the base (8), and each motor is connected to the grinding rollers inside the graded grinding chamber (3) through a coupling (10); The graded grinding chamber (3) is equipped with a graded screen and a spiral conveyor, and is provided with a ore return channel to return particles that do not meet the set particle size requirements to the grinding area. The intelligent slurry conditioning chamber (2) is connected above the grading and grinding chamber (3), and an online slurry dispersion monitoring device is installed inside it; The cyclone flotation chamber (1) is connected above the intelligent slurry conditioning chamber (2). It is a biomimetic flow guide structure and is equipped with a stirring device for generating a cyclone field and a mechanical scraper (4) for scraping the foam layer.

2. The graphite beneficiation equipment according to claim 1, characterized in that, The graded grinding chamber (3) also includes an automatic adjustment device (7) for adjusting the gap between the grinding roller and the grinding disc in real time to meet the grinding requirements of different particle sizes of ore.

3. The graphite beneficiation equipment according to claim 1, characterized in that, The intelligent slurry mixing tank (2) is equipped with an online monitoring device for real-time monitoring of slurry dispersion and feedback control of the addition ratio of water and composite additives.

4. A mineral processing method applied to the graphite beneficiation equipment according to any one of claims 1-3, characterized in that, Includes the following sequential steps: a. The raw ore is continuously fed into the grading and grinding chamber (3) from the feed inlet (6), and is screened in real time by the built-in grading screen during the grinding process; b. Among the screened products, qualified mineral powder that has met the set scale integrity requirements (≥92%) is directly transported to the intelligent slurry mixing chamber (2) through the screw conveyor; coarse particles that do not meet the requirements are returned to the grinding area through the reflux channel for further grinding. c. In the intelligent slurry mixing tank (2), the ratio of water to composite additives is automatically adjusted according to the online monitoring of slurry dispersion to form a homogeneous slurry suitable for flotation. d. The homogeneous slurry enters the cyclone flotation chamber (1). Under the action of the cyclone field, the bubbles and graphite particles undergo directional adsorption. The foam layer enriched with graphite is scraped off by the mechanical scraper (4) and collected as concentrate.

5. The mineral processing method according to claim 4, characterized in that, In step b, the particle size judgment standard for qualified mineral powder is that the mineral powder has reached the particle size and flake integrity that can be directly and effectively floated, without relying on independent grinding time control.

6. The mineral processing method according to claim 4, characterized in that, In step d, the gas-liquid ratio is maintained at 3:1 by controlling the air intake and slurry flow rate of the cyclone flotation chamber (1).

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